Heat exchange unit



Dec. 16, 1952- G. A, BORG 2,621,900

HEATEXCHANGE UNIT Dec. 16, G A BORG HEAT EXCHANGE UNIT 2 SHEETS--SHEET 2 Filed Feb. 25, 1948 Patented Dec. 16, 1952 HEAT EXCHANGE UNIT Gustave A. Borg, Vlatertown, Conn., assigner to Turbo-Ray, Inc., New Rochelle, N. Y., a corporation of New York Application February 25, 1948, Serial No. 10,641

2 Claims.

The present invention relates in general to heat-exchangers and more particularly to a heatexchange unit adaptable for use with both heating and cooling systems.

An object of the invention is to provide a superior space heat-exchange unit which is characterized by its simplicity of construction, durability, economy of manufacture and high efficiency.

A further object of the invention is to provide a superior space heat-exchange unit of which the capacity for heating or cooling may be increased or decreased at will. Y

A still further object of the invention is toprovide a space heat-exchange unit with ilexible heat-exchange tubes to enable the tubes to be readily replaced when defective or worn out and to facilitate the addition and removal of tubes when adjusting the capacity of the unit to a particular area to be heated or cooled.

A still further object of the invention is to p-rovide a space heat-exchange unit with flexible heat-exchange tubes having superior couplingmeans for readily attaching and detaching the tubes to the headers of the unit.

With the above and other objects in View, as will appear to those skilled in the art from the Ipresent disclosure, this invention includes all features in the said disclosure which are novel over the prior art.

In the accompanying drawings, in which certain modes of carrying out the present inventio are shown for illustrative purposes:

Fig. 1 is a perspective view of the improved space heat-exchange unit of this invention with the hinged door of the unit closed;

Fig. 2 is a perspective view of the heat-eX- change unit of Fig. l, but with the door open so as to show the tubes of the heat-exchanger and the pipe connections thereto;

Fig. 3 is an enlarged broken side elevation partly in section of the heat-exchange unit on section line 3-3 of Fig. l showing details of the upper and lower headers and the flexible tubes connected therebetween;

Fig. 4. is a broken plan view of the unit on section line -ll of Fig. 3 showing the lower header;A

Fig. 5 is a broken front elevation of the unit on section line 5-5 of Fig. 3;

Fig. 6 is a fragmentary perspective view of one end of one of the exible tubes of the heat-excange unit showing the integral head formed on the end of the tube;

Fig. 7 shows a modification of the tubestructure and the assembly thereof in la modied seat 2 of one of the headers of the heat-exchange unit; and

Fig. 8 is a perspective View of the heat-exchange unit showing some of the tubes removed and the eXing of one tube for eifecting the removal thereof.

The heat-exchange unit of this invention is designed to be connected into a hot-water or steam-heating system and used as a space heater; or to be connected into a suitable cooling system to serve as a space-cooling unit, the unit being interchangeable to either use without modification. For purposes of brevity, however, the description of the unit which follows herewith relates to its installation in a heating system, the unit being referred to as a space heater.

The space-heater unit of this invention is designed to be connected into a hot-water or steamheating system, whether or not the heating system is a new or old installation, and at selectedl points thereof corresponding to the spaces to be heated. More particularly, the space-heater is a self-contained unit of pleasing external appearance so that if desired, it may be installed in a room simply by standing the unit against the wall as is done with the conventional hot water and steam radiators; and is proportioned so that it may, with a minimum of effort and expense, be set into a recess in the Wall of a room between the studs and substantially flush with the vertical fa-ce of the wall.

Referring to the drawings, the heater unit is indicated generally at l@ and comprises a sheetmetal box consisting of sheet-metal side panels I I, a sheet-metal back panel I2 and a perforated sheet-metal bottom panel I3, the side, back and bottom panels being secured together by fastening means such, for example, as welded or soldered joints. Although sheet aluminum is a preferred material, it will be understood that stainless steel or like metals may be used. Further, it is within the purview of the invention to form the box from a single casting or by drop forging.

The front panel l of the bOX comprises a sheetmetal door which is provided with an upper and lower set of perforations I5 and I respectively, one edge of the front panel being hinged as at Il to the f ront edge of the corresponding side panel II of the box. Mounted on the door against the inside face thereof and superposed over thelower set of perforations IE is a substantially-rectangular perforated shutter I8. The latter is arranged to slide transversely of the door Id to align or misalign the respective apertures of the door and of the shutter; and to operate by means of two knobs I9 which are secured at opposite ends respectively of the shutter and project forwardly through two transverse slots adjacent opposite edges respectively of the door. The bottom panel I3 is provided with a set of perforations and with vertical apertures 2| and 22 at opposite ends respectively of the panel, the apertures 2| and 22 being adapted to accommodate the inlet and outlet pipes 23 and 24 respectively of the heating system.

Supported in the sheet-metal box I0 is a heatexchanger indicated generally at 25 and comprising upper and lower headers 26 and 21 respectively connected by substantially-vertical heatexchange tubes 28. Both the upper and lower headers are formed of a suitable metal which has low-heat radiation characteristics, which is relatively light in weight, of low cost and easy to fabricate. Cast aluminum is a metal meeting these requirements and is preferred in the present embodiment of the invention, although it will be appreciated that other metals may be used.

The upper cast-aluminum header 25 comprises a substantially-rectangular hollow block having a relatively-thick bottom-wall portion 29 and a relatively-thin top-Wall portion 30 spaced verticaly above the bottom-wall portion 29 by relatively-thin front and rear side-wall portions 3| and 32 respectively to form a continuous chamber 33 extending longitudinally of the header. Circumscribing the four sides of the bottom-wall portion 29 of the upper header is a continuous recessed groove 34 which intersects the bottom corners of the header to provide a peripheral seat for accommodating the upper edges of the back and side wall panels of the box and the upper edge of the door, the upper edges of the side panels and the back panel being secured in the peripheral groove 34 by screws 35 or equivalent fastening-means. The front-wall portion 3| of the upper header is provided with a rearwardlycurved brow 35 which is blended into the top-wall portion of the header to enhance the appearance of the unit.

The bottom-wall portion 29 of the upper header is provided with a plurality of vertical apertures 31 extending in parallel rows longitudinally of the header and in transversely staggered relationship, each aperture 31 comprising a relatively-small bore 38 opening at its upper end into the longitudinal chamber 33 of the header and at its lower end into a conical seat 39 at the upper end of a counterbore 43. The latter is provided with internal screw-threads 4|, the lower end of the counterbore intersecting the underside of the bottom-wall portion of the header.

The chamber 33 of the upper header 26 is adapted to be vented and to this end an air-valve 63 of conventional construction is inserted into an aperture in the bottom wall 23 of the upper header, preferably adjacent one end thereof, as shown especially well in Fig. 5.

The lower header 21 is similar essentially to the upper header and comprises a substantiallyrectangular hollow block having a relatively-thick top-wall portion 42, a relatively-thin bottom-wall portion 43 spaced vertically from the top-wall portion 42 by relatively-thin front and rear sidewall portions 44 and 45 respectively to form a chamber 45 extending longitudinally of the lower header. In the lower header, however, the chamber 45 is divided into a right-hand cell 41 and a left-hand cell 48 by means of an integral substantially-vertical partition 49, the latter having a. small aperture 5D extending therethrough for connecting the right-hand and left-hand cells of the chamber, for the purpose hereinafter described. Formed at the opposite ends of the bottom-wall portion 43 of the lower header are vertically internally-threaded apertures 5| and 52 respectively adapted to bey arranged in axial alignment with the respective apertures 2| and 22' in the bottom panel of the box and to receive the respective upper externally-threaded ends of the inlet pipe 23 and outlet pipe 24 of the heating system.

The lower header is adapted to be secured within the lower part of the box so as to permit air to flow upwardly both from the perforations 20 in the bottom of the box and from the perforations I6 in the bottom of the door around the rear side and the rightand left-hand ends of the lower header. To these ends, the longitudinal and transverse dimensions of the lower header and in particular the top-wall portion 42 thereof, are less than those of the corresponding section of the box I0 so as to provide a, vertical clearance-space 53 between the rear of the header and the rear panel l2 of the box and vertical clearance-spaces 54 and 55 between the respective opposite ends of the header and the corresponding side panels ef the box. To support the lower header 21 in the box in the aforesaid manner, suitable lugs 56 are formed integrally at and extend from the four corners of the top-wall portion 42 of the header so as to engage the adjacent walls of the box, each lug being fastened securely thereto by screws 51 or equivalent fastening-means. The top-wall portion 42 of the lower header is also provided with a plurality of vertical apertures indicated generally at 58, arranged in rows extending longitudinally of the header and staggered transversely with respect to each other, each aperture comprising a relatively-small bore 59 opening at its lower end into the chamber 45 and at its upper end into a conical seat E0 at the bottom of an internally-threaded counterbore G l As shown especially well in Figs. 3 and 4, the apertures 31 of the upper header and the apertures 58 of the lower header are arranged in axial alignment and adapted to support the respective upper and lower ends of the heatexchange tubes 23 which connect the upper and lower headers.

The tubes 28 are preferably formed of thinwalled copper tubing, although aluminum tubing and steel tubing as well as other metals may conceivably be used, and are corrugated circumferentially, the corrugations being of helical orientation longitudinally of the tube. Thus, each tube is capable of being flexed transversely of its length and to automatically expand or contract longitudinally thereof. Moreover, the corrugated surface of each tube insures a maximum surface area per tube so as to accelerate the transfer of heat by convection from the tube to the air currents owing past the tube.

The upper and lower ends of each tube are provided with coupling-heads 62, each comprising a substantially-cylindrical collar, the diameter of which is greater than the over-all diameter of the tube so as to form an annular substantially-square shoulder' 63 therewith; and slightly less than the internal diameter of the counter-bores 40 and 6| of the respective headers so as to fit snugly therein, as hereinafter described. Each coupling-head G2 is preferably formed of an easily-malleable material such, for example, as lead or an alloy of lead and tin, and

is preferably attached to an extremity of the tube by casting or otherwise molding the coupling-head integrally thereon, as indicated clearly in Fig. 3. The underside of each couplinghead may be an annular square shoulder, but is preferably provided with a slight radius, as indicated at 64 in Fig. 6.

The coupling-means of each tube comprises the aforesaid coupling-heads thereof and a pair of coupling-nuts indicated generally at 65 and adapted to cooperate therewith, each couplingnut consisting of an externally-threaded cylindrical shank-portion 6B having a polygonal flange 61 at the inner end thereof. The internal diameter of each coupling-nut is slightly greater than the over-al1 external diameter of a corrugated tube so as to slide freely therealong, the external diameter of the threaded portion of the shank corresponding substantially to the diameter of the internally-threaded counterbore of the headers, so as to threadedly engage therein. A pair of coupling-nuts are adapted to be mounted on each tube with the flange El of one nut opposed to the ange 61 of the second nut, each coupling-nut being effectively held from sliding oif its respective end of the tube by engagement with the annular square shoulder 63 of the corresponding coupling-head 62 of the tube.

Because of the inherent flexibility of the tubes 28 and the simplicity of the coupling-means therefor, the assembly and disassembly of each tube between the upper and lower headers of the heat-exchange unit may be accomplished with facility and dispatch. Thus, to assemble a tube between the headers of the heat-exchanger, the tube, including its coupling-nuts, is inserted between the headers, the coupling-head 62 at one end of the tube, as for example its lower end, being inserted into one of the counterbores of the lower header. Thereupon, the coupling-nut 65 at the lower end of the tube is threadedly engaged in the counterbore 6i of the lower header and screwed down firmly therein, thereby pressing the malleable coupling-head E2 of the tube against the conical seat 60 of the counterbore, the pressure applied to the malleable head of the tube by the coupling-nut being suiiicient to mold the coupling-head to the conical seat. The tube is then bent or flexed transversely, as indicated in Fig. 8, to bring the upper end of the tube, and more particularly the malleable coupling-head 62 thereof, into registry with an axially counterbore 40 of the upper header, whereupon the upper coupling-nut $5 is threaded into the counterbore to mold the upper head 62 of the tube to the conical seat 39 of the counterbore 40.

The removal of any one tube of the heat-exchanger can be effected with equal dispatch simply by loosening the coupling-nuts and then flexing the tube to pull its upper and lower coupling-heads out of the counterbores of the corresponding headers of the heat-exchanger. It will be evident, therefore, that by providing a heating-unit with headers having a sufficiently large number of tube-apertures to accommodate the maximum number of tubes required for heating a given area, the heating-unit may be used at its maximum capacity or at any required fraction thereof simply by removing a predetermined number of tubes. In such instances, the vacated tube-apertures of the upper and lower headers may be closed by blind-plugs eil, as shown in Figs. 4 and 5.

When the heating-unit is connected into a hot-water system, hot water is delivered by way of the inlet pipe 23 into the right-hand cell 41 of the lower header and from thence passes up through the group of tubes connected thereto into the right-hand end of the chamber 33 of the upper header. The Water then flows to the left-hand end of the chamber 33 and passes down through the left-hand set of tubes into the left-hand cell 4S of the lower header from which it returns to its heating source by way of the outlet pipe 253. Any air which may be entrapped in the upper chamber is enabled to escape through the air-valve 69. Cold air entering the perforations I6 and 29 respectively at the bottom of the box flows upwardly through the clearancespaces 53, 5d and 55 around the lower header and over the bank of heat-exchanging tubes 28, whereupon heat is transferred, by convection, from the hot tubes to the air, the heated air escaping from the box through the perforations itl in the upper part of the door. Thus, a continuous supply of warm air flows into the space to be heated. In this connection, it should be pointed out that when the unit is installed in a recess in the wall of a building, cold air from the spaces formed in the wall at the juncture of the sills, joists and stringers passes up through the perforations in the bottom panel of the box to augment the circulation of air over the heated tubes of the heating-unit. The rate of circulation of warm air may be effectively controlled by adjustment of the sliding-shutter I8.

As used in a two-pipe steam-heating system, the heating-unit operates substantially in the manner described above for a hot-water heatingsystem, the steam being fed into the unit by way of the inlet pipe 23 and escaping from the unit by way of the outlet pipe 24. The heatingunit is also adapted to be used with the socalled single pipe steam-heating system wherein steam is fed to the heating-unit by way of the inlet pipe 23. Inasmuch as this system does not provide for a return pipe, the aperture 52 of the lower header is closed by means of a blind plug (not shown) and the condensed steam formed in the chamber of the upper header flows down through the left-hand bank of tubes into the left-hand cell :t8 of the lower header and subsequently passes through the aperture 5i) of the partition 49 to drain out of the chamber of the lower header by way of the inlet pipe 23.

Referring to Fig. '7, the latter shows a, modied heating-tube and coupling-means therefor for use with the heating-unit, the tube comprising a thin-walled copper tube 19 having circumferential corrugations arranged transversely to the longitudinal axis of the tube. The opposite ends of each tube constitute substantially smooth cylindrical sleeve-portions 1l, the external diameter of each sleeve-portion Il being substantially equal lto the over-all diameter of the corrugated tube. The free end of each sleeve-portion 'il is provided with an annular outwardly-flared coupling-skirt 'l2 which is adapted to cooperatively engage a conical seat 'i3 formed at the intersection of a bore 14 and an internally-threaded counterbore 'i5 of a modified header, a fragmentary portion of which is shown at it. In this modification, the conical seat '.53 of the header is seen to be the reverse of the conical seats of the apertures in the headers hereinabove described. The couplingmeans used to assemble the corrugated tubes l@ in the internally-threaded counterbores 15 of the header la comprise coupling-nuts 'Il adapted to be assembled on the tube, each nut comprising an hexagonal flange 18 and a cylindrical externally-threaded shank-portion 79, the latter being adapted to be threadedly engaged in the counterbore 15 of the header 16 and having an annular internally-beveled surface B at its free end. The latter cooperatively engages the annular coupling-skirt 12 of the tube to press the latter tightly into engagement with the conical seat 'i3 of the header 16. The mode of assembling the tubes 19 in the header and disassembling the tubes therefrom is substantially similar to that hereinabove described.

as mentioned at the outset, although the he t-exchange unit is described as a space he ter, the unit is equally applicable to cooling sys ems, in which instance, a coolant would be circulated through the flexible corrugated tubes of the heat-exchange unit to cool or refrigerate the space surrounding the unit.

The invention may be carried out in other specific ways than those herein set forth without departing from the spirit and essential characteristics of the invention, and the present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.

I claim:

1. In a heat exchange unit, the combination including: a substantially closed casing having perforations in upper and lower portions thereof for controlling the circulation of air therethrough; said casing includinga front wall portion comprised by a hinged front panel for opening for access to the interior of the casing; a heat exchanger in said casing, said heat exchanger comprising a pair of headers secured in the upper and lower portions, respectively, of said casing; said upper header constituting the upper and closure wall of said casing; transversely flexible heat exchange tubes for inter-connecting said headers; said heat exchange tubes being positioned within said casing opposite said hinged front panel of said casing; and coupling means on said tubes arranged to engage said headers to inter-connect said tubes thereto, said tubes being exible transversely of their length to permit disengagement of said coupling means from said headers for disassembling said tubes therefrom and to permit reengagement of said coupling means with said headers for reassembling said tubes therein.

2. In a heat exchange unit, the combination including: a substantially closed casing including a front wall comprised by a hinged front panel for opening for access to the interior of said casing, said panel being provided with upper and lower perforations for controlling the circulation of air through said closed casing; a shutter associated with the lower perforations of said front panel for regulating the flow of air therethrough; a heat exchanger in said casing comprising a pair of headers secured in the upper and lower portions, respectively, of said casing, said lower header being supported in spaced relation to the walls of said casing for circulation of air through the perforations in the lower part of said front panel upwardly past said lower header to said upper header, and from thence out of the perforations in the upper part of said front panel; said upper header being constructed and mounted to constitute the top closing wall of said casing; transversely flexible heat exchange tubes for inter-connecting said headers, said heat eX- change tubes being disposed in said casing opposite said hinged front panel; and coupling means on said tubes arranged to engage said headers to inter-connect said tubes thereto, said tubes being flexible transversely of their length to permit disengagement of said coupling means from said headers for disassembling said tubes therefrom and for reengagement of said coupling means with said headers for reassembling said tubes therein.

GUSTAVE A. BORG.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 419,336 4Shackleton Jan. 14, 1890 1,389,997 Sedwick Sept. 6, 1921 1,564,446 Rhoads Dec. 8, 1925 1,632,803 Ray June 21, 1927 1,798,892 Murray, Jr. Mar. 3l, 1931 1,812,509 Benson June 30, 1931 1,886,645 Clarkson Nov. 8, 1932 1,913,573 Turner June 13, 1933 1,927,991 Pendleton Sept. 26, 1933 1,950,768 Anderson Mar. 13, 1934 1,991,339 Ullman Feb. 12, 1935 2,144,030 Potter J-an. 17, 1939 2,188,176 Cornell, Jr. Jan. 23, 1940 

